Sailing to the stars on the scale of human lives could be a matter of choosing the right wind.
Researchers from McGill University in Canada and the Tau Zero Foundation in the US have proposed a new way to span the extraordinary distances of interstellar space, using a lot of nothingness and a touch of seabirds.
One of the most promising spaceflight solutions to date uses the spectrum of starlight streaming from the Sun. Though their effect is small, their sheer numbers and high speed make photons an intriguing source of energy to build up the high speed needed to traverse void light-years in a short amount of time.
Although functional, all solar sails share a common disadvantage: the sail itself. Solar sails must stretch meters to capture the photons needed to propel a vehicle.
They also need the right shape and material to convert the tiny momentum of each photon into motion. And they have to dissipate heat well enough not to warp and break.
This is not only a headache for materials science; all of these requirements add bulk. Even with the lightest known materials, the highest speeds we could achieve with our sun’s radiation would be just over 2 percent Speed of light, meaning it would still take a few centuries to travel to the nearest star.
Needless to say, sailing to the stars would be a lot easier if we could omit the sails part.
Luckily, another type of storm is blowing from the sun’s surface, one that isn’t made up of photons but rather an ion plasma whipped into frenzy by the sun Cracking and cracking of the sun’s magnetic fields.
Although far fewer high-speed electrons and protons are emitted from the Sun than photons, their charged masses pack a greater punch.
Such particles would normally be a problem for typical sails, as they transfer their charges to the material’s surface, like static electricity on a wool sweater in winter, create drag and change the shape of the sail.
But as anyone who has tried to push the poles of magnets together knows only too well, an electromagnetic field can resist without requiring a large, solid surface.
And so it’s goodbye shiny stuff and hello superconductor. A cable just a few meters long could theoretically create a field wide enough to deflect the sun’s charged wind on the order of tens to hundreds of kilometers.
The system would act more like a magnetic parachute, one being pulled by a stream of particles traveling at nearly 700 kilometers per second, or just under a quarter percent of the speed of light.
That’s not bad, but as birds like the albatross knowthe winds don’t set the speed limits when it comes to flying high.
By channeling in and out masses of air moving at different speeds, seabirds can absorb the energy of a headwind, known as a headwind dynamic flight to gain speed before returning to their original trajectory.
Using a similar trick in the “headwind” of termination shock – and turbulent zones of contrasting stellar winds used by astronomers to define the edge of our solar system – a magnetic sail could exceed the speed of the solar wind and potentially bring it within reach of solar sails simply by radiation.
Although the technology doesn’t appear to be much faster than the “traditional” solar sail method at first, other forms of turbulence at the edges of interstellar space could provide a greater boost.
Even without a gentle nudge from dynamic soaring, viable plasma-based technology could bring Cube-Sat satellites around Jupiter within months instead of years.
As in the age of sailing, there are many ways we can harness the currents that wash through the vast expanse of space.
And yet the seabirds show us the way.
This study was published in Frontiers in Space Technologies.